1. Field of the Invention
The invention relates generally to glassware forming machines of the rotating table type having a plurality of continuously rotating, circumferentially spaced forming units. More particularly, the invention relates to an apparatus for driving a delivery system for delivering gobs of molten glass to the continuously rotating blank molds of the machine.
2. Description of the Prior Art
Glassware forming machines of the rotating table type are well known in the glassware manufacturing industry. One type of such machine is shown in U.S. Pat. No. 1,979,211 and is commonly referred to as the "Emhart H-28 Machine." This type of machine is a single table, continuous rotary motion machine having a plurality of individual sections or forming units mounted for rotation about the axis of the machine. These machines have been available with different numbers of individual forming units, thus constituting, for example, a 6, 12 or 18 section machine. In such H-28 machines each individual forming unit produces one glassware article for each complete revolution or cycle of the machine and will therefore be referred to herein as H-28 single gob machines.
A significant improvement over the H-28 single gob machine is disclosed in U.S. Pat. No. 4,339,264 which describes an H-28 double gob machine where each individual forming unit produces two glassware articles for each complete cycle. This patent is hereby incorporated by reference in this disclosure in its entirety.
One of the unique features of the prior art H-28 double gob machine is its delivery system, that is, the manner in which it guides or delivers gobs to the continuously rotating blank molds of the machine. Each set of inner and outer blank molds has associated with it a gob guiding unit consisting of a scoop, trough and deflector for guiding gobs into the blank molds. Each gob guiding unit oscillates over a predetermined arcuate path about a delivery system axis parallel to the machine axis so that in one arcuate direction the speed of the deflector of the gob guiding unit approximates that of the continuously moving blank mold to facilitate gob delivery.
The delivery of gobs to the blank molds of a continuously rotating H-28 machine, whether single or double gob, is quite important. The gob must be delivered by the gob guiding unit while the blank molds are moving. In the H-28 single gob machine this may be accomplished by matching the arcuate speed of the gob guiding unit (in at least the direction where it moves with the blank) to that of the continuously moving blank mold. The same problem exists in H-28 double gob machines although compounded by the fact that, in addition to both gobs having to be delivered while the corresponding molds are moving, both gobs should be delivered at the same time with respect to each other.
The prior art machine was provided with a cam and cam follower mechanism for oscillating the gob guiding units along a predetermined arcuate path. This structure, regardless of the cam profile selected, caused undesireably high aceleration forces to be applied to the gob guiding units as well as the gobs sliding thereon. The prior art H-28 single gob machine used a crank and crank roller to effect this oscillatory motion. A straight bar, pivotable at one end and spring biased at the other, served as the means by which the motion of the crank roller was transferred to the gob guiding unit in the single gob machine. This mechanism was satisfactory for low speed operation of the single gob machine but proved undesireable at the high speeds of the double gob machine. Accordingly, it is an object of this invention to provide a crank drive arrangement for causing the oscillatory motion of the gob guiding units. It is another object of this invention to provide a crank arrangement for driving the gob guiding units with lower acceleration than prior art devices.